An air conditioning round register includes a cylindrical retainer, an opening and closing fin supported such that the fin is able to be tilted in the retainer, a control that is rotated with fingers, and a mechanism that converts the rotation of the control into the tilt of the fin (Patent Document 1).
The control often used is a round knob provided such that the round knob protrudes farther forward than a front end of the retainer from a center portion of the register (Patent Document 1). Since the round knob is held between two fingers for its rotation, holding and rotating the knob are not easy. Moreover, since a direction (i.e. radial direction) in which holding force is applied is different from a direction in which the knob is rotated, a greater load is applied to the fingers during the rotation. Increasing the size of the cylindrical knob to reduce the load to the fingers causes pressure loss and increased noise.
The present applicant has proposed another control that is made of a thin plate extending in an axial direction of the air passage, and is formed in a substantially triangular frame having a space therein through which the air can flow (Patent Document 2). Since this control with the substantially triangular frame is held between three fingers, holding and rotating the control are easier than the round knob. Moreover, since this control requires less amount of the holding force when rotated and allows most of the whole force to be applied in a rotational direction, it reduces the load to the fingers than the round knob. However, the control with the substantially triangular frame has insufficient fitting feel with fingers, because the surfaces of the triangular frame are almost flat even though they are concave to some extent. Moreover, the control has difficulty of fitting fingers to the control, because the control is almost housed in a space near the front end of the retainer. Thus, the control with the substantially triangular frame has been required to be improved to be easily held and rotated.